Switch and operating mechanism for circular hosiery knitting machine speed control

ABSTRACT

A mercury switch which operates the speed control of a circular hosiery knitting machine is positioned within an elongated chamber of a switch housing. The switch housing, in turn, is pivotally mounted to the frame of a knitting machine at such a position as to be operated by a lever responsive to progression of the pattern chain and/or cam drum, and alternately tilted between a &#34;switch activated&#34; and &#34;switch deactivated&#34; position. The mercury switch is so arranged within the housing that when the housing is lowered to the deactivated position, the mercury is disengaged from the contacts of the switch, and when the housing is raised to the activated position, the mercury is caused to move by gravity down into engagement with the contacts of the switch. The mercury switch is completely sealed within the housing, so that oil, oil vapors, dust and the like cannot work thereinto.

BACKGROUND OF THE INVENTION

In certain types of circular knitting machines, notably the TextileMachine Works knitting machine, types of Mark III, Mark IIIS, and MarkIV, a microswitch is mounted on the machine adjacent the pattern chainand cam drum, and is operated through a lever mechanism, selectivelyactivated by protruding lugs on the pattern chain and cams on the drum.The lever mechanism, when thusly activated, engages the contact arm ofthe microswitch to complete a circuit, sending impulses to a solenoid toselectively shift the drive belt of the needle cylinder between a fastand slow speed pulley.

Considerable difficulty has been encountered with the microswitch inthat either oil works its way into the interior of the microswitch andcauses a carbon buildup on the contacts, preventing good electricalcontact between the activator arm and one of the contacts, or else theactivator arm, which is a thin metallic plate, breaks after a short timedue to the constant wear.

As a result such microswitches must be replaced on the knitting machinesperiodically, sometimes as often as monthly, causing added expense anddown time of the machine. Further, if the contact strip breaks duringusage, the drive belt is not shifted from the fast to the slow speedpulley prior to the pattern shift and considerable damage can be done tothe needle cylinder, resulting in the machine being down for severalhours.

Efforts to solve this problem have, so far, been unsuccessful.

SUMMARY OF THE INVENTION

The present invention, however, is directed to an improved switchingdevice, which replaces the conventional microswitch arrangement. Towardthis end, a switch housing having an elongated chamber therein receivesa mercury type switch and is pivotally mounted to the machine forarcuate movement between a first position in which one end of thechamber is tilted downwardly and a second position in which the one endis tilted upwardly The mercury switch is so mounted within the chamberthat the leads thereof exit through the end of the chamber opposite theone end which is tilted upwardly and downwardly. Therefore, when the oneend of the chamber is tilted downwardly the mercury is out of engagementwith the contacts of the leads and when the same one end is tiltedupwardly the mercury is moved down the tube into engagement with thecontacts completing the circuit to the solenoid which shifts the drivebelt. The switch housing includes a depending finger which is engaged bythe conventional lever arrangement during operation for moving theswitch housing between the aforementioned first and second positionsresponsive to movement of the lever by lugs on the pattern chain andcams on the cam drum.

It is, therefore, an object of the present invention to provideimprovements in the switching arrangement of the speed control mechanismfor circular hosiery knitting machines.

It is further an object of the present invention to provide an improvedswitching device for the speed control mechanism of circular hosieryknitting machines in which the switch is sealed and without relativemovement of switch parts, thereby minimizing deterioration or wearduring operation.

Other objects and a fuller understanding of the invention will becomeapparent from reading the following description of a preferredembodiment in view of the accompanying drawings in which:

FIG. 1 is a perspective view, partially in schematic, and with partsbroken away, illustrating the switch mechanism according to the presentinvention, and its relationship to the pattern chain, cam drum and drivebelt control solenoid;

FIG. 2 is an enlarged, cross-sectional view of the switch mechanismitself removed from the knitting machine; and

FIG 3 is a perspective view of the switch housing itself, illustrating aportion of the frame of the machine onto which the switch housing ismounted.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Turning now to a discussion of the preferred embodiment of theinvention, there is schematically illustrated in FIG. 1 a conventionalcam drum 10 having a plurality of cam tracks 12, and the pattern chain14 having a plurality of lugs 16 protruding upwardly from one edgethereof. A lever 18 is conventionally attached to the machine in somesuitable manner, so that a first downwardly extending leg 20 ispositioned in the path of lugs 16 as the pattern chain moves. A seconddownwardly extending leg 22 is similarly positioned in the path of camson one of the cam tracks 12.

The switch mechanism 24, according to the present invention, ispivotally mounted to the knitting machine at the same, already availablemounting position as occupied by the replaced microswitch on mostmachines. It should be pointed out that on the aforementioned Mark IVmachine, an adapter bracket (not shown) must be provided as the regularmounting holes on the Mark IV are oriented angularly rather thanhorizontally. A protuberance 26 or other portion of housing 24 isengaged by or rests against the upper surface of lever 18. The switchhousing 24 includes a mercury switch sealed therein and having the leadsthereof connected to a solenoid S, which operates in a conventionalmanner to shift a drive belt back and forth between a slow speed pulleyand a fast speed pulley responsive to alternate pulses from theswitching mechanism. The operation of lever 18 by the pattern chain 14and cam track 12 is conventional and well known, and the applicant ofthe present invention does not make any claim to this facet of thestructure. Also, the solenoid and the manner in which it operates thedrive belt between the fast and slow speed pulleys responsive to signalsor pulses from some type switch mechanism is also conventional.

What is new in the present invention is the switching mechanism itself,and the way it provides protection for the switch therein, so as toprovide longer life and trouble free operation.

Specifically referring to the switch mechanism, the switch housing 24includes an elongated body portion 28 with an elongated interior chamber29 therein. A projection 30 protrudes upwardly from and extendstransversely across the upper wall of body portion 28 and includes anopening 30a therethrough through which a fastener 31 extends topivotally attach the housing 28 to a position on the knitting machineformerly occupied by the replaced microswitch. As illustrated in FIG. 3,the shaft of fastener 31 is threaded at the end 33 and is unthreaded orsmooth in the intermediate portion which extends through opening 30a andprovides a bearing surface for housing 24 as it pivots responsive tomechanical activation from the pattern chain and cam drum. The threadedmounting hole in the machine frame is already present, and does not haveto be drilled when retro-fitting machines in the field with the newswitch mechanism.

A mercury switch 32 having a connecting end 37, from which leads 34,36extend, and a free end 39 is mounted within chamber 29 so that the freeend 39 is positioned at one end of the chamber 29, while the connectingend is positioned toward the other or open end 27 of the chamber withleads 34,36 extending outwardly through the open end of housing 28, fromwhich they are connected to solenoid S. A small amount of sealingmaterial 40 is spread around the connecting end 37 of mercury switch 32after it is inserted into chamber 29 to seal the switch 32 therein andretain it within the chamber 29 so that it does not inadvertently becomeremoved therefrom. As is the case with mercury switches, a bulb or dropof mercury 38 is included within the switch, and as long as the switch32 is tilted with the free end 39 downwardly, the mercury remains out ofengagement with the contacts of leads 34,36. When the free end 39 istilted upwardly, the mercury 38 moves by gravity down to the connectingend and completes an electrical circuit across the contacts of leads34,36.

An abutment means in the form of a finger 26 extends downwardly from thelower wall of housing 28 for engagement by lever 18 as will be discussedhereinafter. The finger 26 is longitudinally positioned toward the freeend 39 of the mercury switch (the one end of the chamber) from the pointof mounting through opening 30a so that when the finger 26 is in itsdownward-most position (as when lever 18 is not activated upwardly bypattern chain 14 of cam track 12,) the one end of the housing is alsotilted downwardly. At this point it should be noted that the projection30 and opening 30a are positioned off center of housing 28 toward theend 27 from which the leads 34,36 extend, so that normally the one endof housing 24 will tend to tilt downwardly, as the center of gravity ofthe housing 28 is to the right of the attachment point. When lever 18activates the lug upwardly, the one end of housing 24 is moved to suchextent that it is tilted upwardly, and the drop of mercury 38 is moveddown into engagement with the contacts of leads 34,36. It is importantto note here that the positioning of finger 26 with respect to the pivotprojection 30, the size of the housing, and the size and length of themercury switch 32 are all so related with each other that the lever 18,when activated, moves the mercury switch 32 to such an extent that theright hand end is lifted from a normal downwardly tilted position to aswitch activated, upwardly tilted position. After the lug 16 on patternchain 14 or cam 13 on cam track 12 passes, the switch housing 24 isagain returned to its normal position.

In operation, then, during normal formation of the stocking when most ofthe knitting occurs and the drive belt is on the fast speed pulley, thelever 18 is in its lowermost position, so that the switch housing 24 hasthe one end (right hand end in FIG. 1) tilted downwardly. At some timeslightly before a pattern change occurs, it is necessary to slow downthe speed of the needle cylinder, and a lug 16 on pattern chain 14 or acam 13 on cam track 12 causes the lever to move its upper position,whereupon the switch housing 24 becomes tilted upwardly, causing themercury 38 in mercury switch 32 to move into engagement with thecontacts of leads 34,36, thereby activating the solenoids to shift thedrive belt to the slow speed pulley for the pattern change. Uponcompletion of a preselected number of courses, when it is desired tochange the condition of the solenoid, another lug on pattern chain 14 orcam track 12 activates switch housing 24 again in the same manner toshift the solenoid to the opposite mode or position.

It should be noted that the switch mechanism according to the presentinvention, as in conventional practice, can be activated either fromlugs 16 on the pattern chain 14 or cams 13 on cam track 12. The reasonfor this is that some of the pattern changes are controlled by thepattern chain 14, while some operations, necessitating a slow down inspeed, are operated from the cam track 12.

Obviously the specific shape, size, and other characteristics andfeatures of the switch housing could be altered significantly withoutdeparting from the scope of the invention. It is only necessary that amercury switch be seated in some type of housing and positioned on themachine so that the mercury switch is normally tilted downwardly withthe mercury out of engagement with the contacts of leads 34,36. Then,when it is time to signal the solenoid, the switch is moved to aposition in which the free end of the switch is tilted upwardly and themercury moved into engagement with the contacts of leads 34,36.

Thus, there are no moving parts to wear out as is the case withmicroswitches. Oil mist and vapors cannot work their way into the switchcausing carbon deposits which eventually lead to malfunction, and thereare no small springs or other parts to wear out. The life of the switchand switch housing according to the present invention is, therefore,almost unlimited, and should last substantially the life of the machine,thereby leading to considerable economic advantages over switches whichaccomplish the same function in accordance with known techniques.

Although a specific embodiment of the present invention has been shownand described hereinabove, it is recognized that certain modificationsand changes could be made without departing from the scope of theinvention, which is to be limited only by the following claims:

That which is claimed is:
 1. In combination with a circular hosieryknitting machine, an improved cylinder speed control system of the typehaving lugs on the pattern chain and/or cams on the cam drum, avertically reciprocal lever mechanism pivotally mounted to said machinein the path of said lugs and cams and activated in response toengagement by said lugs and cams, a switching mechanism in the path ofand operated by said lever mechanism, and a speed control mechanismelectrically connected to and operated by electrical pulses from saidswitching mechanism to shift a drive belt between a slow and fastpulley, wherein said switching mechanism comprises:a. a housing havingan elongated chamber therein and pivotally mounted to said machine forarcuate reciprocal movement between a first position in which one end ofsaid chamber is tilted downwardly and a second position in which saidone end is tilted upwardly; b. a glass encapsulated mercury switchhaving leads extending therefrom and mounted in said chamber with saidleads extending through the other end of said chamber opposite said oneend, whereby, when said one end of the chamber is tilted downwardly, themercury in said switch is out of engagement with the contacts of saidleads, and when said one end is tilted upwardly, the mercury is incontact with said leads; c. said housing including an abutment meansthereon, engaged by said lever during operation, for moving said housingbetween said first and second positions responsive to movement of saidlever by said pattern chain and cam drum.
 2. In the combination of claim1, the switching mechanism wherein said switch housing includes apivotal mounting means positioned between the center of gravity of saidhousing and the other end of said housing, whereby said one end normallytends to tilt downwardly, and said abutment means is positioned betweensaid pivotal mounting means and said one end.
 3. The combinaton of claim1 in which said other end of said chamber includes a sealing means toseal said glass encapsulated mercury switch therein.
 4. In combinationwith a circular hosiery knitting machine, an improved cylinder speedcontrol system of the type having lugs on the pattern chain and/or camson the cam drum, a vertically reciprocal lever mechanism pivotallymounted to said machine in the path of said lugs and cams and activatedin response to engagement by said lugs and cams, a switching mechanismin the path of and operated by said lever mechanism, and a speed controlmechanism electrically connected to and operated by electrical pulsesfrom said switching mechanism to shift a drive belt between a slow andfast pulley, wherein said switching mechanism comprises:a. a glassencapsulated mercury switch having leads extending from contacts sealedtherein through a base end, and a free end opposite said one end; b.support means for pivotally mounting said mercury switch generallyhorizontally with the free end being movable between and off positiontilted below the horizontal and an on position tilted above thehorizontal; and c. said support means having a lever engaging positionpositioned in the path of said lever and being movable verticallyresponsive to the reciprocal movement of said lever, whereby a liftingof said lever will cause a resulting tilting upwardly of the free end ofsaid mercury switch.